In the field of locating a cable fault in an underground or other buried cable, it is known to locate the fault using a ground microphone, whereby the user has no initial information about the position of the sensor over the cable or conductor line and no information about the position of the fault. In order to find the location of the fault, the user of the device gradually approaches closer to the fault by making successive measurements, in a “trial and error” process, namely in that the user successively moves the ground microphone to successive measurement positions, and then determines and compares successive coincidence measurement values at the successive measurement positions. The coincidence measurement value represents the time difference between the arrival of the magnetic field pulse that is generated around the cable by an electrical pulse fed into the cable, and the acoustic pulse that is generated by a sparking arc or flash-over or the like at the cable fault due to the electrical pulse in the cable. If the coincidence measurement values become smaller from one measuring position to the next, then the user knows that he is getting closer to the cable fault. On the other hand, if the coincidence measurement values become larger, then the user knows that he is moving farther away from the cable fault.
In the above known process using the known equipment, it is problematic that the user has no information about the actual position and layout of the cable itself. Thus, the user might move transversely to the cable line from one measuring position to the next, or inadvertently move away from the path or layout of the cable, for example especially where the cable makes a curve. In such a case, the user thus obtains larger difference measured values, which suggest to him, that he is moving farther away from the cable fault location. However, these measurements and the resulting measured values are faulty, because of the progressive motion to successive measuring positions relative to the unknown position and layout of the cable.
To avoid the above problem, it is known to trace out the position and layout of the cable in a previous process by means of an acoustic frequency transmitting and receiving system. Thereby, the user first determines the position and layout of the underground or other buried cable, and records or marks the cable position and layout for later reference when subsequently carrying out the separate cable fault locating process as described above.
Thus, for locating the cable fault, it is generally necessary to carry out two successive time-consuming measuring processes one after the other, namely first locating and tracing out the location and the layout of the cable itself, and thereafter performing the actual cable fault locating process. This is time consuming and requires two distinct sets of equipment, and therefore becomes expensive and cumbersome.